I will highlight relevant findings. The first finding was that mice with Helios-deficient Foxp3+ TREG showed additional resistance to tumor (however, please note that tumor growth pattern and mice survival do not correlate in Heliosfl/fl.FoxP3-Cre mice).

In summary, the authors proposed that therapeutic targeting of Helios expression in tumor-associated FoxP3+ TREG could convert them from tolerogenic cells into anti-cancer fighting cells (however, please note the authors did not formally test whether anti-cancer effect of anti-GITR antibody was indeed mediated via its effect on Helios in FoxP3+ TREG).